1 files changed, 129 insertions, 0 deletions
diff --git a/drivers/media/usb/gspca/pac_common.h b/drivers/media/usb/gspca/pac_common.h
new file mode 100644
index 000000000..31f2a42af
--- /dev/null
+++ b/drivers/media/usb/gspca/pac_common.h
@@ -0,0 +1,129 @@
+/*
+ * Pixart PAC207BCA / PAC73xx common functions
+ *
+ * Copyright (C) 2008 Hans de Goede <j.w.r.degoede@hhs.nl>
+ * Copyright (C) 2005 Thomas Kaiser thomas@kaiser-linux.li
+ * Copyleft (C) 2005 Michel Xhaard mxhaard@magic.fr
+ *
+ * V4L2 by Jean-Francois Moine <http://moinejf.free.fr>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* We calculate the autogain at the end of the transfer of a frame, at this
+   moment a frame with the old settings is being captured and transmitted. So
+   if we adjust the gain or exposure we must ignore atleast the next frame for
+   the new settings to come into effect before doing any other adjustments. */
+#define PAC_AUTOGAIN_IGNORE_FRAMES	2
+
+static const unsigned char pac_sof_marker[5] =
+		{ 0xff, 0xff, 0x00, 0xff, 0x96 };
+
+/*
+   The following state machine finds the SOF marker sequence
+   0xff, 0xff, 0x00, 0xff, 0x96 in a byte stream.
+
+	   +----------+
+	   | 0: START |<---------------\
+	   +----------+<-\             |
+	     |       \---/otherwise    |
+	     v 0xff                    |
+	   +----------+ otherwise      |
+	   |     1    |--------------->*
+	   |          |                ^
+	   +----------+                |
+	     |                         |
+	     v 0xff                    |
+	   +----------+<-\0xff         |
+	/->|          |--/             |
+	|  |     2    |--------------->*
+	|  |          | otherwise      ^
+	|  +----------+                |
+	|    |                         |
+	|    v 0x00                    |
+	|  +----------+                |
+	|  |     3    |                |
+	|  |          |--------------->*
+	|  +----------+ otherwise      ^
+	|    |                         |
+   0xff |    v 0xff                    |
+	|  +----------+                |
+	\--|     4    |                |
+	   |          |----------------/
+	   +----------+ otherwise
+	     |
+	     v 0x96
+	   +----------+
+	   |  FOUND   |
+	   +----------+
+*/
+
+static unsigned char *pac_find_sof(struct gspca_dev *gspca_dev, u8 *sof_read,
+					unsigned char *m, int len)
+{
+	int i;
+
+	/* Search for the SOF marker (fixed part) in the header */
+	for (i = 0; i < len; i++) {
+		switch (*sof_read) {
+		case 0:
+			if (m[i] == 0xff)
+				*sof_read = 1;
+			break;
+		case 1:
+			if (m[i] == 0xff)
+				*sof_read = 2;
+			else
+				*sof_read = 0;
+			break;
+		case 2:
+			switch (m[i]) {
+			case 0x00:
+				*sof_read = 3;
+				break;
+			case 0xff:
+				/* stay in this state */
+				break;
+			default:
+				*sof_read = 0;
+			}
+			break;
+		case 3:
+			if (m[i] == 0xff)
+				*sof_read = 4;
+			else
+				*sof_read = 0;
+			break;
+		case 4:
+			switch (m[i]) {
+			case 0x96:
+				/* Pattern found */
+				gspca_dbg(gspca_dev, D_FRAM,
+					  "SOF found, bytes to analyze: %u - Frame starts at byte #%u\n",
+					  len, i + 1);
+				*sof_read = 0;
+				return m + i + 1;
+				break;
+			case 0xff:
+				*sof_read = 2;
+				break;
+			default:
+				*sof_read = 0;
+			}
+			break;
+		default:
+			*sof_read = 0;
+		}
+	}
+
+	return NULL;
+}